Marie Nováková, Autumn 20201
Structural and functional organisation
of the living systems.
Homeostasis.
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Life is a dynamic system with focused behavior, with autoreproduction,
characterized by flow of substrates, energies and information.
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ligand
hydrophilic
glycocalyx ion
hydrophobic
I – integral protein
R – receptor
E – enzyme
K – channel (kanál)
P – pump (ATP-ase)
Membrane
lipids
Proteins
PLASMATIC MEMBRANE
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GIT, lungs, kidney, skin
Plasma 5% - 3.5 litres
Interstitial 15% - 10.5 litres
fluid
Intracellular 40% - 28 litres
fluid
Evans blue, 131J
Inulin, manitol, sacharose
Antipyrin, D2O
Total volume of
fluids
Extracellular
fluid (incl. plasma)
COMPARTMENTALISATION OF BODY FLUIDS
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BODY FLUIDS
BODY COMPOSITION
Water 60% (80-50%) of body mass
Proteins 18%
Lipids 15%
Minerals 7%
152
5 2
117
27
0 0
14
157
30
5 10
74
113
0
20
40
60
80
100
120
140
160
mEq/l
Concentration of cations and anions in body fluids
Extracelulárně
Intracelulárně
Na K Ca Cl HCO3 Prot. PO4
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TRANSPORT MECHANISMS
ACTIVEPASSIVE
DIFFUSION
OSMOSIS
FILTRATION
REGULATED
FACILITATED DIFUSION
COTRANSPORT
SYMPORT
ANTIPORT
ATP-ases
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PASSIVE TRANSPORT MECHANISMS
Differences in body fluids composition result from features
of barriers and forces responsible for transport.
DIFUSION
Transport of gases, substrates, metabolites (up to m.w. 60 thous.
in direction of concentration gradient of diluted compound.
It depends on solubility in water and lipids.
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OSMOSIS
Transport of water across semipermeable membrane in direction to
higher concentration of diluted substance(e.g. in direction to lower
concentration of water). It depends on number of particles.
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FILTRATION
Movement of solvent as a result of osmotic and hydrostatic pressure.
Production and resorption of interstitial fluid (Starling forces).
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REGULATED TRANSPORTS
COTRANSPORT transported compound uses concentration
gradient of Na+ as the driving force
FACILITATED DIFUSION selective carrier
limited capacity
amino acids
phosphate
SYMPORT in the same direction
ANTIPORT in opposite direction
glucose, AA
Ca2+, H+
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Na+/K+ ATP-ase (exchanger)
Similar transports:
•Ca2+/H+
•Na+/K+
•K+/H+
•Na+/H+
AGAINST concentration gradient
ACTIVE TRANSPORTS
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IONIC CHANNEL
Molecular biology of the cell. B. Alberts et al., Garland Science 2002
Membránová elektrofyziologie myokardu, P. Pučelík, Avicenum, 1990
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GATING
Molecular biology of the cell. B. Alberts et al., Garland Science 2002
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COMMUNICATION AMONG THE CELLS
MECHANICAL CONNECTION
• desmosomes (macula adherens; cell adhesion and mechanical
stability of tissues) – epidermis, liver, myocardium
ELECTRICAL CONNECTION
• gap junction (nexus) (in intercalar disc; consists of conexons)
HUMORAL CONNECTIONS (REGULATION)
• autocrine
• paracrine
• endocrine
• juxtacrine
• neurocrine
• neuroendocrine
NERVOUS CONNECTIONS (REGULATION)
Receptor, ligand, second messenger
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INTEGRATION OF HUMORALAND NERVOUS SYSTEMS:
• synapse
• hypothalamus - pituitary gland
• adrenal medulla
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REGULATION
Control of living systems.
Living systems – open systems; their existence depends on flow
of energy and substances between organism and environment in
both directions.
Appears at all levels of system (cell – whole organism).
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FEEDBACK
NEGATIVE
POSITIVE
Deviation from desired value oscillates or continuously increases.
POSITIVE FEEDBACK
RARE !!!
PHYSIOLOGICAL
Ensuring of systems, activation
PATHOLOGICAL
Instability - death